\begin{tikzpicture}[>=Stealth]
    \draw [->] (-3.5,0) -- (3.5,0) node[anchor=north] {$x$};
    \draw [->] (0,-2) -- (0,2) node[anchor=east] {$y$};
    \node at (-0.3,-0.3) {$O$};
    \draw (0,0) .. controls(0.8,-2.6) and (1.3,0.5) .. (2.5,-0.6);
\end{tikzpicture}
